Trophic position and prey preferences of snappers (Teleostei: Lutjanidae) in a connected bay-to-reef Caribbean system

Abstract

The trophic position (TP) and proportional contribution of prey for six species of snappers were assessed at two interconnected coastal environments of the Mexican Caribbean: the mangroves of Río Huach Channel and Chetumal/Corozal Bay, and the seagrass beds of the adjacent Xcalak Reef Lagoon. This study provides a trophic scenario using stable isotopes, under the hypothesis that use of resources would vary by habitat. We evaluated the relative proportion of carbon and nitrogen of assimilated resources and TP. According to the stable isotope mixing models, snappers showed a higher consumption of secondary consumers at the expense of primary consumers. Snappers are piscivorous-invertivorous mesopredators and the most piscivorous species were Lutjanus griseus and L. jocu, which displayed a higher TP. Lutjanus griseus had a higher TP than the other snappers both in the bay and the reef lagoon, whereas Ocyurus chrysurus showed the lowest TP, with a major preference for crustaceans. Our findings revealed differences in resource use by snapper species rather than by habitat. Understanding TP and differential use of resources by snappers is key to understanding the dynamics and function of connected ecosystems to implement effective conservation and management strategies.